Add support for 24/8 textures in the GE debugger.
d3d: Support depth and stencil in the GE debugger.

But, not with our current depth surfaces.
d3d: Use INTZ if supported.

No performance impact on my card, and allows downloading depth/stencil
data.
d3d: Add a not-working experiment to blit depth.
Merge pull request #6909 from unknownbrackets/debugger

d3d: Use INTZ depth textures where supported